1. Field of the Invention
The present invention relates generally to a coin return protection device and more particularly, to a device which can be attached to existing payphone coin return doors to prevent tampering with the coin return mechanisms.
2. Description of the Prior Art
The payphone coin return mechanisms in use today typically comprise a hollow body having front and back walls and top and bottom walls which are joined by opposing side walls. An intermediate wall is situated between the top and bottom walls and extends from a point below the back of the top wall downwardly toward the front wall to define with the top wall and the side walls a throat for the coin return chute. The bottom wall of the chute extends downwardly from the front wall and then rearwardly upwardly toward the back wall. It thus forms with the intermediate and side walls a trough portion for the chute, the trough extending below and forwardly and rearwardly of the throat.
The front wall of the chute is provided with an opening which is normally closed by a pivotally mounted door and through which a finger of a caller can be inserted to retrieve returned coins delivered to the trough. Another opening is provided at the rear of the top wall of the chute. This opening receives coins which are being returned to a caller from the payphone's coin return mechanism. After the returned coins pass through this opening they fall onto the intermediate wall of the throat and slide downward to the trough at the bottom wall for retrieval by the caller as already described.
Theft of coins from payphone coin return chutes as a result of "stuffing" the coin return chute has been a continuing problem in payphones having coin returns of the type described above. Stuffing has been a serious problem for many years, and until now no effective way of preventing it had been found. To "stuff" a payphone, the would-be thief inserts a compressible obstruction through the coin return door, past the opening in the front wall and trough, into the throat of the chute. The obstructing material is typically wadding, paper, fabric or plastic sheeting, and it is used to prevent the coins which would otherwise be returned to the payphone user from falling through the coin return chute. After sufficient time passes a sizable number of coins accumulates behind the obstructing material. The blockage is removed and the freed coins cascade into the return. The obstructing material can be cleared out either manually or by using implements such as a pick or hook. Some individuals ignite the foreign material so that it burns and turns to ash. This latter technique may also damage the payphone's internal mechanisms.
Early attempts at preventing this type of theft centered around designing the payphone coin return mechanism in such a way that it became disabled when the chute was stuffed. This type of solution is described, for example, in U.S. Pat. Nos. 1,887,576; 1,901,944; 1,921,071; 1,921,072; and 2,004,615. Although disabling the coin return mechanism prevented the theft of coins, it also made it impossible to return coins to the caller in the event a call was not completed Disabling the coin return mechanism was not an entirely satisfactory solution to the theft problem, since it was not feasible in pay stations where access to an operator was not available.
More recent attempts to prevent this type of theft involved designing a return chute which is more difficult to stuff. In particular, the back wall of the chute below the intermediate wall was brought forward, reducing the area of the trough available for a thief to work in when attempting to insert the stuffing material. The back wall was replaced by an opening closed by a pivoting door so that the obstructing material might pass out of the chute. These modifications, however, have not proved successful and there is still a need for a more effective way of preventing the stuffing of payphone coin return chutes.
U.S. Pat. No. 4,761,809 describes another attempt to design an "unstuffable" coin return. A tubular member having pointed teeth at its front end is inserted into the coin return chute; the teeth point toward the coin return door. A blade having additional sharpened teeth is attached to the lower surface of the intermediate wall of the throat. All these teeth are intended to slice up obstructing material so it cannot form blockages, but actual usage of the invention reveals that these teeth facilitate stuffing because they catch and hold the wadding.
The payphone stuffing problem is an old one and until now no satisfactory solution has been found. This crime costs the phone companies enormous sums of money. Although the phone companies would not normally collect the returned money lost to the "stuffers," since in properly working payphones the coins are returned for uncompleted calls, the phone companies usually have to refund the lost money to their customers. Furthermore, each phone company must employ personnel to investigate reports of payphones failing to return change, employ maintenance workers who examine and repair "stuffed" phones, and have accounting and payment systems in place to refund lost money to payphone users. The overall administrative cost of repairing payphones and refunding lost money are quite high, and there is a substantial need for an inexpensive device that reliably prevents stuffing which can be quickly and simply installed in an existing payphone.